Improvement in grate-bars



M. ERDMAN. GRAN-BARS.

INU. 194,344, Patented Aug. 21,1877.-

UNITED STATES PATENT OFEIGE.

EDWARD M. ERDMAN, 0F LYKENS, PENNSYLVANIA.

I IMPROVEMENT IN GRATE-BARS.

Specification forming part of Letters Patent No. ll94,344, dated August21, 1877; application filed July 2, 1877.

To all whom tt may concern Be it known that I, EDWARD MARION EED- MAN,of Lykens, in the county of Dauphin and State of Pennsylvania, haveinvented a new and valuable Improvement in Grate-Bars; and I do herebydeclare that the following is a full, clear, and exact description ofthe construction and operation ofthe same, reference being had to theannexed drawings, making a part of this specification, and to theletters and figures of reference marked thereon.

Figure 1 of the drawings is a representation of a plan view of myinvention. Fig. 2 is a side elevation, and Fig. 3 is an end view upon anenlarged scale.

This invention has for its object to construct a furnace-grate bar thatwill be light, and at the same time strong and durable; and consists inproviding the gratebar with a hollow cylinder, placed underneath thesame, so that it will resist the 'warping and twisting from the heatmuch better than the ordinary form,

` as it allows the free circulation of air through the opening in thecylinder, said cylinder being made removable, so that it can be used foranother grate, as will be hereinafter described, and subsequentlypointed out in the claim. 1

In the accompanying drawings, A represents the long parallel bars,which, if desired,

may be formed concave upon their upper surface. These bars have theusual transverse supports B to hold them in place, said supports havingsuitably-formed openings a to allow the free circulation of the air fromone to the other. Thesupports B are also formed with annular openings b,to receive a horizontal metal tube or hollow cylinder, C, placed looselytherein, so that the cast-iron portion of the bar is free to expand andcontract. The openings b in the supports B are slightly larger than thecircumference of the tube, to allow the bar to slide on the pipe,whatever the expansion and contraction may be. This metal tube rendersthe grate-bar very light, and more' air-surface is obtained, in additionto getting a direct line for expansion and contraction, therebyovercoming warping and twisting, as the air is allowed to freelycirculate through the tube, which is not the case where a solid cylinderor bar is used.

The tube can be removed and used for another grate-bar when the tiresurface of said bar is burned off.

Having now fully described my invention,

what I claim as new, and desire to secure by

